Is Microsoft waving their finger in disapproval at people looking to slim down Vista? That seems to be what is happening as many people frustrated with Vista's slowness turn to third-party utilities to speed things up. In particular, a program called vLite has earned a bit of fame by allowing people to make their Vista installations more lightweight, removing unwanted components and implementing various speed tweaks.

it is possible that a Windows Media Player component (for example you did not install the Media Player with vLite) has a security leak, this .dll needs patching, on a full Vista the media player will be patched through the windows update site. this component is also used by other applications, so all is well.

but on your vLite it doesn't find media player so can't patch, so the security leak remains, thus not patching the bug.

It came to my attention that some users experienced a few issues with the latest SP3 version.
It was all caused by the Security Center removal. So keep that component if you use this SP3 build until the next update. Previous builds worked fine.

It came to my attention that some of you expected to install Service Pack on the lite Vista, without some components.
Unfortunatelly that is not possible, nor it was ever expected to be because Service Pack is meant to update the whole installation, if it detects that something is missing it aborts.